Physiological and behavioral parameters of pain and stress in mares during and after transvaginal ultrasound-guided follicular aspiration.
Authors: Van den Branden Emma, Salamone Matthieu, Broothaers Klaartje, Peere Sofie, Polfliet Ellen, Dewulf Manon, Van Steenkiste Glenn, van Loon Gunther, Smits Katrien, Govaere Jan
Journal: Frontiers in veterinary science
Summary
Transvaginal ultrasound-guided follicular aspiration (TVA) is now routinely used in equine reproductive practice for oocyte collection, yet concerns persist about mare welfare given the invasive nature of the procedure involving restraint, perineal preparation, transrectal palpation, and repeated needle punctures. Eight mares underwent three TVA procedures (two with follicle puncturing and one without) whilst researchers measured serum glucose, lactate and cortisol concentrations, facial pain scores, heart rate and heart rate variability at multiple timepoints before, during and after each procedure. Contrary to expectations, needle puncturing itself produced no significant changes in any pain or stress parameter, and heart rate did not increase at the moment of needle insertion; instead, both punctured and non-punctured procedures triggered significant elevations in cortisol and lactate levels, facial pain scores and heart rate during the restraint and perineal preparation phases, with all physiological responses returning to baseline within 24 hours. The key implication for practitioners is that stress responses during TVA are primarily driven by the procedural manipulations rather than the needle punctures themselves, suggesting that refinements to handling protocols and restraint methods may offer greater welfare improvements than focusing solely on the aspiration component of the procedure.
Read the full abstract on PubMed
Practical Takeaways
- •The needle punctures themselves do not appear to cause additional pain or stress during TVA procedures—the main stressor is the physical manipulation and restraint
- •Mares recover quickly from TVA procedures with all physiological parameters returning to normal within 24 hours, suggesting good welfare recovery despite acute stress during the procedure
- •Focus welfare management efforts on minimizing the duration and intensity of restraint and perineal preparation rather than the aspiration punctures themselves
Key Findings
- •Needle puncturing during TVA did not significantly increase cortisol, lactate, heart rate, or facial pain scores compared to non-puncturing procedures (p > 0.05)
- •Physical restraint and perineal preparation induced significant increases in cortisol, lactate, heart rate, and facial pain scores in both puncturing and non-puncturing procedures (p < 0.05)
- •All stress and pain responses were acute and returned to baseline within 24 hours post-procedure
- •Manipulations alone (without puncturing) were sufficient to induce measurable stress responses in mares